Field Rutting Research Articles

Determination of Virgin Asphalt Mixture Content in Hot In-Place Recycling Based on Field Rutting Depth Variability

Hot in-place recycling (HIR) technology, 100% recycling reclaimed asphalt pavement (RAP), has been widely used as a sustainable maintenance treatment. However, the inhomogeneity of RAP makes it impossible to securely assume that the produced mixture properties will match the laboratory design. For HIR projects, a virgin asphalt mixture (VAM) is added to modify the gradation of the existing rutted pavement. However, once the quantities of VAM added to areas of rutting are varied along the driving direction, the desired construction quality cannot be maintained. In this paper, a method to estimate the quantities of VAM needed for areas with rutting along the driving direction is proposed. To verify the feasibility of the proposed method and explore the effects of varying VAM content caused by rutting depth (RD) distribution variation on construction quality, performance tests of all samples, including two gradation types of virgin aggregates and five VAM contents, were conducted in the laboratory. Test results indicate that the pavement performance of the recycled mixture with continuously graded virgin aggregates is more stable due to the similar gradation of RAP, while the performance of the recycled mixture with gap-graded virgin aggregates possesses substantial fluctuation. Specifically, when the required VAM content is lower than 15%, namely, all monitored RDs less than 10 mm, gap-graded virgin aggregates are more highly recommended from a high-temperature stability perspective. When the required VAM content ranges from 10% to 15%, namely, all monitored RDs ranging from 5.9 to 10 mm, the continuously graded virgin aggregates should be considered first with respect to low-temperature performance. To improve moisture susceptibility, the continuously graded virgin aggregates are more appropriate.

Effects of Field Aging on Material Properties and Rutting Performance of Asphalt Pavement

This study evaluates field asphalt aging based on material property changes in pavement with time, and investigates if such changes could have an impact on field rutting performance. Four projects from three different climate zones were monitored as part of the NCHRP 9-49A project at two stages: during pavement construction and two to three years after opening it to traffic. Construction information were collected, and field cores were drilled at both stages to evaluate the material properties of recovered asphalt binder and asphalt mixture. Field rut depth was also measured. In addition, pavement structure, climate and base/subgrade modulus information were also obtained. Results indicate that the asphalt mixture stiffening is caused in major part by asphalt aging. However, the effect of asphalt aging on pavement mixture property may not follow a proportional liner trend. The parameters that are most sensitive to field ageing are MSCR R3.2 and dynamic modulus. It is also found that the variables which showed a good ranking trend with the field rut depth are climate condition (relative humidity, high temperature hour, solar radiation), material properties (Hamburg rut depth, rutting resistance index, high temperature performance grade, MSCR, and dynamic modulus, base and subgrade moduli), as well as air voids.

Correlating the Asphalt-Binder MSCR Test Results to the HMA HWTT and Field Rutting Performance

Asphalt binder is one of the key constitutive components of hot-mix asphalt (HMA) that considerably affects its rutting performance. In particular, the high-temperature rheological properties measured from the multiple stress creep and recovery (MSCR) test are critical for correlating to the HMA rutting resistance. In this study, the Texas flexible pavements and overlays database was used as the data source to investigate the effect of asphalt-binder high-temperature rheological properties on the HMA rutting resistance. The study methodology was based on correlating the results of the MSCR test and the Hamburg wheel-tracking test (HWTT) to HMA field rutting performance. The data matrix for the study included asphalt binder (PG 64-22) from three different sources, three widely used Texas HMA mixes (fine gradation to coarse gradation), and five in-service highway test sections constructed using the same asphalt binders and HMA mixes. In general, the MSCR nonrecoverable creep compliance parameter, Jnrdiff, showed fairly strong correlations with the HMA rutting performance in the laboratory and field. The percent recovery parameter (R), on the other hand, exhibited the potential to ascertain and quantify the presence of modifiers in the asphalt binders. Furthermore, the test results indicated that material source/supplier has an impact on the rheological properties of the asphalt binders with the same performance grade (PG). Overall, the use of the MSCR test to quantify the asphalt-binder high-temperature rheological properties indicated the potential to compliment the laboratory HWTT test for correlating with the field HMA rutting performance in terms of the effects of asphalt binder.

Field performance of bitumen emulsion Cold Central Plant Recycling (CCPR) mixture with same day and delayed overlay compared with traditional rehabilitation procedures

Cold Recycled Mixtures (CRM) offer many benefits, including cost-effectiveness and sustainability. Large existing Reclaimed Asphalt Pavement (RAP) stockpiles that represent an environmental and storage challenge can be used for bitumen emulsion Cold Central Plant Recycling (CCPR). A pavement rehabilitation demonstration project using Cold Recycled Mixture with Bitumen Emulsion (CRM-E) as binder course with 100% RAP was carried out on August 25, 2020. The project was divided into three sections to evaluate the mill and pave strategy using CRM-E as an alternative to traditional Hot Mixture Asphalt (HMA). The wearing course was the same asphalt concrete for the three sections. The difference between Section 1 and 2 that used CRM-E was to either pave the asphalt concrete overlay on the same day or to delay its application for 3 days to give additional time for the CRM-E to cure. Section 3 had no CCPR and consisted of two HMA layers. The field performance of the rehabilitated sections was monitored in 4 phases after 14 days, 3 months, 6 months and 12 months. The performance of the sections was assessed based on Falling Weight Deflectometer (FWD), field rutting measurements and cracking distress surveys. Cores were also taken over time to compare the CRM-E and HMA binder course properties in terms of resilient modulus, dynamic creep, indirect tensile strength and tensile strength ratio. The research showed that CRM-E and HMA performance was similar in terms of FWD deflections, field rutting, in situ cracking, and moisture resistance of the field cores. CRM-E showed superior performance in terms of resilient modulus and dynamic creep compared with asphalt concrete binder course based on testing of field cores taken after 6 and 12 months. The research showed that same day CRM-E HMA overlay is a viable construction option.

Application of Dynamic Stability Criterion in Evaluating Field Rutting of Asphalt Pavements Using the Wheel Tracking Test

Application of Dynamic Stability Criterion in Evaluating Field Rutting of Asphalt Pavements Using the Wheel Tracking Test

Correlating the asphalt-binder high-temperature properties (DSR) to HMA permanent deformation (RLPD) and field rutting: A laboratory-field study

Asphalt-binders are part of the key material constituents affecting the performance of hot-mix asphalt (HMA), and ultimately, the field performance of flexible pavement structures. Quite often, it is desired/useful to predict the HMA permanent deformation (viscoelastic) properties and field rutting from the asphalt-binder properties. Using the Texas flexible pavements and overlays database, namely the Texas Data Storage System (DSS), as the data source, this laboratory-field study was conducted to correlate the asphalt-binder properties to HMA permanent deformation (viscoelastic) properties and field HMA-layer rutting performance of in-service highway sections. Data extracted from the Texas DSS included asphalt-binder high-temperature rheological properties measured using the dynamic shear Rheometer (DSR) test, HMA permanent deformation (PD) and viscoelastic properties from the repeated load permanent deformation (RLPD) test, and field rut depth (RD) data for the HMA layers of in-service highway test sections. Two Texas asphalt-binder types, four HMA mixes, and four in-service field highway sections were used in the study. For some parametric comparisons, the corresponding results indicated good statistical correlations among the asphalt-binders, HMA mixes, and field rutting performance, with a coefficient of determination (R2) over 60%. Overall, the study findings indicated that the HMA PD properties and field HMA-layer rutting can be predicted from the asphalt-binder high-temperature rheological properties, with a linear or logarithmic model, to an accuracy exceeding 60%.

Field and simulated rutting behavior of hot mix and warm mix asphalt overlays

Research implementing new pavement technologies often focuses on material characterization; however, expanding the research to study and validate how new technologies influence pavement design is needed for continual improvement. Numerical analysis approaches use laboratory mixture data to predict field performance. This study compares predicted rutting by MEPDG design, estimated rutting from Finite Element (FE) simulations, and actual rutting performance in the field. Ten years ago, warm mix asphalt research was underway to measure the effect of warm mix asphalt (WMA) additives and lower production temperatures on performance. WMA benefits include reduced mixing/compaction temperatures, reduced fuel consumption, and improved compatibility. In 2009, three asphalt overlay projects were constructed in Iowa using both hot mix asphalt (HMA), and WMA mixes to compare their performance. A series of dynamic modulus tests were conducted to determine dynamic modulus and phase angles of HMA and WMA mixtures. The dynamic modulus results were used to develop FE viscoelastic simulations to predict the rutting of HMA/WMA pavement sections. Iowa’s pavement management system provided field rutting of WMA/HMA sections. Also, pavement sections were evaluated using mixture input parameters in the Mechanistic-Empirical Pavement Design Guide (MEPDG). The results showed MEPDG based on linear elastic theories might overestimate the rutting of asphalt pavements, especially overlays placed on Jointed Plain Concrete Pavement (JPCP). In contrast, the FEM based on viscoelastic theories more accurately predicted the rutting of pavements. Calibration coefficients are proposed by this study, which may be useful for design engineers and industrial applications to correct and modify MEPDG overlay design thicknesses for HMA/WMA mixes placed on HMA and JPCP surfaces.

Comprehensive evaluation of wheel-tracking rutting performance assessment tests

This study aimed to advance the implementation of the most promising wheel-tracking rutting assessment tests in the newly proposed Balanced Mixed Design (BMD) (or Performance-Engineered Mix Design method [PEMD]). In order to achieve this goal, the study examined the validity of two rutting assessment tests (i.e. Hamburg Wheel Tracking test [HWTT], and Asphalt Pavement Analyzer [APA] rut test) and three performance indicators (i.e., HWTT rut depth after 15,000 passes [HWTT15000], HWTT rut depth at 20,000 passes [HWTT20000], and APA rut depth after 8,000 cycles [APA8000]). A total number of 33 asphalt mixes including six Laboratory Mixed-Laboratory Compacted (LMLC), 10 Plant Mixed-Laboratory Compacted (PMLC), and 17 field projects were evaluated in this study. The results demonstrated that HWTT and APA rut test rutting performance indicators were sensitive to the variation in binder content and binder PG. Also, APA8000 results had low/moderate variability, while HWTT15000 and HWTT20000 had moderate variability. In addition, HWTT and APA rut test performance indicators were correlated with the observed field rutting of the evaluated field projects. Several pass/fail performance assessment thresholds were proposed including maximum rut depth of 5 mm, 10 mm, and 12.5 mm for APA8000, HWTT15000, HWTT20000, respectively. Also, the results showed that both HWTT and APA rut test provided similar rutting assessment for the evaluated mixes. The study recommended using HWTT over APA rut test since HWTT can be also used to evaluate the resistance to both rutting and moisture damage. Also, the study recommended using HWTT15000 over HWTT20000 as a performance indicator, since it requires less testing time.

Effects of In-Place Volumetric Properties on Field Rutting and Cracking Performance of Asphalt Pavement

AbstractThe effects of in-place volumetric properties on the rutting and cracking of asphalt pavement are of great interest to the pavement industry. As such, the major objectives of this paper are...

Comparison of the Hamburg, indirect tensile, and multi-sequenced repeated load tests for evaluation of HMA rutting resistance

Abstract Rutting is one of the major distresses occurring in hot-mix asphalt (HMA) pavements. In order to minimize permanent deformation generated in HMA layers, various laboratory tests, including the indirect tensile test (IDT), Hamburg wheel tracking test (HWTT), and multi-sequenced repeated load (MSRL) test and so forth have been developed to evaluate the rutting resistant potential of HMA mixture. In this study, 10 HMA mixtures cored from 5 different highways in Jiangsu Province in southeast China were investigated. The methodology of the study incorporated a two-phase approach, namely: (1) laboratory tests and (2) correlation analyses. Based on ANOVA and Tukey’s HSD analyses, for evaluation of the best and worst rutting resistant mixes, the consistency was achieved between HWTT and MSRL results. According to correlation analyses, it is found that both dynamic modulus (DM) from IDT mode at 35 °C and 10 Hz and compound creep stiffness modulus (CCSM) were better correlated with creep rate (CR). Furthermore, compound average strain rate (CASR) exhibited the best potential for prediction of actual field rutting, followed by CCSM, and CR. However, the correlation between DM and the field rutting growth was not as stronger as the above-mentioned indicators.

Studies on Hexagonal Wire Mesh-Reinforced Crushed Stone Dust

Abstract Crushed Stone Dust (CSD), which is a waste product from an aggregate crusher, could be used as a pavement layer. To improve the tensile strength of CSD, it is worthwhile reinforcing it. In the present study an attempt has been made to reinforce a loosely and densely compacted CSD layer with Hexagonal Wire Mesh (HWM) placed in various positions. The results indicate that the California Bearing Ratio (CBR) value is improved by the placement of HWM in CSD. Field Rutting studies were also conducted on test tracks made of unreinforced and reinforced CSD layers. The rut depths were significantly reduced due to the inclusion of the reinforcement in the CSD layer.

Nonrecoverable Compliance and Recovery Behavior of Polymer-Modified and Reclaimed Asphalt Pavement–Modified Binders in Arkansas

Abstract For quality assurance and quality control purposes, suppliers and users of asphalt binders follow the widely used dynamic shear rheometer (DSR) test method (AASHTO T 315, Standard Method of Test for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR)) to capture viscoelastic properties of polymer-modified binders (PMBs) and reclaimed asphalt pavement (RAP)–modified binders even though it is designed for unmodified asphalt binders. AASHTO T 315 is inadequate to characterize modified binders because of the relatively small impact of the phase angle and strain levels on the rutting and fatigue factors, respectively. The recently approved multiple stress creep recovery (MSCR) test (AASHTO T 350, Standard Method of Test for Multiple Stress Creep Recovery (MSCR) Test of Asphalt Binder Using a Dynamic Shear Rheometer (DSR)) results can better relate the laboratory-based and field rutting of PMBs and additive-modified binders. In the current study, Superpave and MSCR tests were performed to evaluate viscoelastic properties of selected asphalt binders certified in Arkansas. A total of 32 binders were tested in the laboratory. Among these, 8 were unmodified binders, 18 were PMBs, and 6 were RAP-modified binders. The nonrecoverable compliance and MSCR percent recovery data of tested binders were analyzed for the grading purpose and establishing the MSCR percent recovery criteria for local service temperature and traffic conditions. The developed guidelines are expected to be helpful for transportation agencies in Arkansas to adopt the MSCR test method in their quality control processes.

Comparison of the Relative Long-Term Field Performance among Various Warm Mix Asphalt (WMA) Pavements

The use of warm mix asphalt (WMA) has increased greatly over the past decade because it provides potential to lower energy demands, reduce emissions, and increase haul distances. However, questions remain about the long-term performance of WMA pavements, including whether different WMA technologies can provide the same field performance. In this paper, field rutting and cracking (transverse and longitudinal) performance data for chemical, organic, and foaming WMA technologies are compared pairwise. Thirty-four WMA-WMA pairs from 13 field test roads are included, which cover different pavement ages, traffic volumes, pavement structures, WMA technologies, and four climate zones across the United States. For the WMA-WMA pairs that exhibited statistically different performance, their material properties were investigated further to identify potential factors that could be used to characterize such field differences. The results indicate that, generally, no statistical performance differences are evident between the WMA-WMA pairs. However, it is worth noting that over the longer term, there are individual projects whose organic pavement sections showed statistically higher amounts of cracking than the chemical and foaming sections. Based on the laboratory testing results on field cores, it is suggested that the greater amounts of transverse cracking exhibited by organic pavements may be caused by organic’s lower mixture fracture work density and lower binder failure strain values compared with those of the chemical and foaming sections. The greater amounts of longitudinal cracking exhibited by the organic pavements may be caused by organic’s higher mixture indirect tensile strength, lower mixture fracture work density, and lower binder fracture energy values compared with those of the chemical and foaming sections.

Evaluation of wheel tracking and field rutting susceptibility of dense bituminous mixes

Rutting in bituminous layers is a major mode of distress, especially in pavements with thick bituminous layers. Different binder and mix rutting specifications are adopted by agencies worldwide to address the issue of rutting in bituminous mixes. The wheel tracking test is also widely used to evaluate the rutting potential of bituminous layers which depends on the aggregate gradation, binder type and also on the method of mix design adopted. The present study was conducted to examine the relationship between laboratory wheel track rutting and field rutting of different mixes prepared with different aggregate gradations, binder types and binder contents selected using different compaction efforts. Fifteen pavement sections with different surface mixes were constructed on a national highway. Loose bituminous mixes collected from the field were compacted to prepare specimens for wheel tracking tests. Two sets of specimens were prepared to have (a) 7% air voids and (b) an air void content similar to that observed in the field 1 day after construction. The rut depths measured using a wheel tracking machine correlated very well with field rut depths measured after 1 year when the laboratory specimens were prepared at the same initial air void content as achieved in the field. As expected, the rut depth measured in the laboratory wheel tracker for specimens prepared with 7% air voids did not correlate well with 1 year rut depths of field mixes which had different initial air void contents. Limiting wheel tracking test rut depths have been identified on the basis of comparison of the field rutting performance of different mixes and the corresponding laboratory rutting performance of the mixes. Limiting criteria have been proposed for two limiting rut depths of 10 and 20 mm and for different traffic levels.

Preliminary Dynamic Modulus Criteria of HMA for Field Rutting of Asphalt Pavements: Michigan’s Experience

This paper presents a comparative study of laboratory results of both dynamic modulus testing and field rutting performances of hot-mix asphalt (HMA) in the state of Michigan. Fourteen field-produced mixtures at various traffic levels and aggregate sizes were evaluated and compared to those of field rutting. These mixtures were collected from job sites and compacted with a Superpave gyratory compactor to imitate the common air void level used in Mich., which is 7%. Dynamic modulus E∗ was measured at temperatures ranging from −5 to 39.2°C and frequencies ranging from 0.1 to 25 Hz. The results show that the dynamic modulus values increased when the designed traffic level for HMA mixtures increased. The field rutting performance was evaluated based on theoretical pavement rutting life index. Two parameters, | E∗ | and | E∗ | /sin (φ) , were compared to the theoretical pavement rutting index. Based upon the preliminary study, it was found that E∗ was a suitable parameter in comparing the field and laboratory ...

Use of Mechanistic–Empirical Pavement Design Guide for Mix Performance Evaluation Using the Dynamic Modulus

The Virginia Department of Transportation has worked toward end-result specifications (ERS) in hot-mix asphalt (HMA) since the mid-1960s. With the recent advances in HMA material characterization and the completion of the new Mechanistic–Empirical Pavement Design Guide (MEPDG) under NCHRP Project 1-37, the ultimate goal of true ERS that are performance related seems more feasible. The use of the HMA dynamic modulus as an HMA quality measure is investigated. An effective reduced frequency (temperature–frequency combination) at which the HMA dynamic modulus best correlates with the MEPDG-calculated HMA rutting is determined for eight climatic conditions. This effective reduced frequency did not coincide with the modified Witczak effective temperature–frequency equation. The effect of HMA layer thickness (51 to 254 mm) on effective reduced frequency was investigated for Roanoke, Virginia. It was found that layer thickness had a minor effect on effective reduced frequency, so that the latter can be assumed independent of layer thickness for all practical purposes. Finally, the HMA rutting calculated by using the effective reduced frequency was found comparable with the MEPDG-calculated HMA rutting with average and maximum differences of 6.5% and 23%, respectively. This difference is acceptable considering the variability in actual field rutting measurements (for the same conditions) as well as accuracy of the MEPDG in determining the average HMA field rutting. Use of the effective reduced frequency can result in considerable time and money savings, especially for quality assurance applications for which testing is regularly performed.

Field Rutting Performance of Various Base and Subbase Materials under Two Types of Loading

Seven full-scale field testing sections were built to evaluate the in situ performance of raw blended calcium sulfate (BCS), stabilized BCS, stabilized reclaimed asphalt pavement (RAP), and stabilized soil as base and subbase materials. Two types of load tests were used to evaluate test sections: cyclic plate load test and rolling wheel load test. The differences in pavement response to cyclic plate and rolling wheel loads were identified. The results indicated that the conventional equivalent modulus of elasticity, where only the thickness of individual layers is considered, is not a good performance indicator. However, its modified formulation proposed here provides the means to account for the relative position of individual layers and turn the conventional equivalent modulus of elasticity into a good performance indicator. The rut depths for the rolling wheel load were much higher than those for the cyclic plate load in all test sections. The difference can be as much as three to seven times between these two types of loading. As such, the effects of principal stress rotation and lateral wander on the permanent deformation in pavement need to be addressed in the design. The results of in situ evaluation showed that the 120-grade ground granulated blast furnace slag stabilized BCS is a good candidate as an alternative to conventional stone base.

Simulative Performance Test for Hot Mix Asphalt Using Asphalt Pavement Analyzer

Abstract Permanent deformation, or rutting, has been and continues to be a problem in the performance of hot mix asphalt (HMA) pavements. This paper presents a summary of work conducted under National Cooperative Highway Research Program (NCHRP) Project 9-17. This research project was undertaken to evaluate the Asphalt Pavement Analyzer (APA) to determine its suitability as a general method of predicting rut potential. There was a need to identify test conditions within the APA that produced results most related to field rutting performance. Ten HMA mixes of known field rutting performance were tested within a full factorial experiment designed to determine the combination of testing conditions for the APA that best predicts field rutting. The experimental plan consisted of different specimen types (beam and cylinder), air void contents in compacted test specimen (4 and 7 %), hose diameters (25 and 38 mm), and test temperatures (high temperature of standard PG grade based upon climate and 6°C higher temperature). Based upon the test results and analysis, a tentative standard method of test was developed and recommended. A standard practice for establishing maximum specified rut depth for APA by highway agencies has also been recommended.

Field Validation of Superpave Shear Test on NCAT Test Track

Abstract When the National Center for Asphalt Technology Test Track was built in 2000, one of the primary objectives was to determine the ability of a number of laboratory tests to predict the permanent deformation of various mixtures. Repeated Shear at Constant Height (RSCH) was included as one of the tests in the laboratory study. The subject of this paper is field validation of the Superpave Shear Tester (SST) based on the field rutting data from the Test Track. Permanent shear strain, slope of the deformation rate, repetitions to a certain strain level, and shear modulus were the parameters evaluated for RSCH. The sensitivity of SST test to asphalt binder type in the various test track sections was analyzed. The relationship between RSCH test results and field rut depth was poor. This was partly due to the good quality of the track construction, thick pavement structure, and mild summers during the loading of the 2000 track, which did not cause any significant rutting. The sensitivity study indicated that PG 76-22 binder performed better than the PG 67-22 binder in the RSCH test. The criteria developed by the Asphalt Institute seem to be in a reasonable range.